Semiconductor device, method for manufacturing semiconductor device, and electronic apparatus

ABSTRACT

There is provided a semiconductor device, including a semiconductor substrate, an interlayer insulating layer formed on the semiconductor substrate, a bonding electrode formed on a surface of the interlayer insulating layer, and a metal film which covers an entire surface of a bonding surface including the interlayer insulating layer and the bonding electrode.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a Continuation of application Ser. No.14/827,883, filed Aug. 17, 2015, which is a Divisional of applicationSer. No. 13/755,881, filed on Jan. 31, 2013, now U.S. Pat. No.9,147,650, issued Sep. 29, 2015, which claims priority from JapanesePatent Application JP 2012-029429, filed in the Japanese Patent Officeon Feb. 14, 2012. The entire contents of these applications areincorporated herein by reference.

BACKGROUND

The present disclosure relates to a semiconductor device, a method formanufacturing a semiconductor device, and an electronic apparatus, whichperforms wire bonding by laminating substrates.

High integration of semiconductor devices has been achieved in twodimensional LSI by the introduction of fine processes and improvementsin package density. In recent years, a physical limitation of therefinements has started to be seen, and three dimensional LSItechnologies have been gathering attention.

Bonding technology is a base technology in three dimensional LSI. Thereare a variety of systems within bonding technology, and technologieswhich bond chips to each other and technologies which bond wafers toeach other have been considered. When a three dimensional LSI isfabricated by laminating device wafers together, there is a system ofdirectly bonding Cu electrodes of the device side, which are formed onthe wafer surface, with each other. In this system, there is a methodwhich flattens the CU electrodes and an interlayer dielectric (ILD) soas to be on the same plane, and which performs hybrid bonding of Cu/ILD(Refer to JP 2006-191081A and JP H1-205465A). In such a bonding process,it may be necessary for the bonding surfaces to be extremely planarsurfaces, in order to improve the bonding strength and to controlbonding defects.

SUMMARY

In the above described semiconductor device in which semiconductorsubstrates are directly bonded to one another, it may be necessary toimprove the bond reliability.

The present disclosure provides a highly reliable semiconductor device,method for manufacturing a semiconductor device, and an electronicapparatus.

According to an embodiment of the present technology, there is provideda semiconductor device, including a semiconductor substrate, aninterlayer insulating layer formed on the semiconductor substrate, abonding electrode formed on a surface of the interlayer insulatinglayer, and a metal film which covers an entire surface of a bondingsurface including the interlayer insulating layer and the bondingelectrode.

Further, the electronic apparatus of the embodiment of the presentdisclosure includes the above described semiconductor device, and asignal processing circuit which processes an output signal of thesemiconductor device.

According to an embodiment of the present technology, there is provideda method for manufacturing a semiconductor device, including forming aninterlayer insulating layer on a semiconductor substrate, forming abonding electrode on a surface of the interlayer insulating layer, andforming a metal film on an entire surface of the interlayer insulatinglayer and the bonding electrode.

According to an embodiment of the present technology, there is provideda semiconductor device including a first semiconductor substrate and asecond semiconductor substrate which are formed by laminating surfacesof bonding electrodes through metal films, the semiconductor deviceincluding the first semiconductor substrate, a first interlayerinsulating layer formed on the first semiconductor substrate, a firstbonding electrode formed on a surface of the first interlayer insulatinglayer, the second semiconductor substrate bonded to the firstsemiconductor substrate, a second interlayer insulating layer formed onthe second semiconductor substrate, a second bonding electrode formed ona surface of the second interlayer insulating layer, a metal film formedon a bonding surface between the first semiconductor substrate and thesecond semiconductor substrate, and between the first bonding electrodeand the second bonding electrode, and an insulating film which is formedon the bonding surface between the first semiconductor substrate and thesecond semiconductor substrate, and on a part in contact with the firstinterlayer insulating layer or the second interlayer insulating layer,and which includes a reaction product between the metal film and thefirst interlayer insulating layer or the second interlayer insulatinglayer.

According to the above described semiconductor device of the embodimentof the present disclosure, and a semiconductor device manufactured bythe above described manufacturing method, a metal film is formed on thesurface where an interlayer insulating layer and bonding electrodes of asemiconductor substrate are formed. When this semiconductor substrate isbonded to another semiconductor substrate at the surface where thebonding electrodes are formed, the interlayer insulating layer and themetal film react due to heating of the bonding surfaces, and aninsulating film is formed. Further, the metal film formed on the bondingelectrodes is maintained in the state prior to heating without reaction.

Further, an electrical connection between the bonding electrodes issecured by the metal film on the bonding electrodes. Contact between theinterlayer insulating layer and the bonding electrodes is prevented dueto an insulating layer as a reaction product of the metal film, and areduction in reliability, such as from bonding defects or leak paths, iscontrolled.

In addition, the reliability of an electronic apparatus to which thissemiconductor device is applied can be improved.

According to the embodiment of the present disclosure, a highly reliablesemiconductor device, method for manufacturing a semiconductor device,and an electronic apparatus, can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional figure which shows a schematic configurationof bonding electrodes;

FIG. 2 is a cross-sectional figure which shows a schematic configurationof bonding electrodes;

FIG. 3 is a cross-sectional figure which shows a schematic configurationof a semiconductor device which includes bonding electrodes of theembodiments;

FIG. 4 is a cross-sectional figure which shows a schematic configurationof semiconductor devices which include bonding electrodes of theembodiments;

FIGS. 5A-5C are manufacturing process charts of semiconductor deviceswhich include bonding electrodes of the embodiments;

FIGS. 6A-6C are manufacturing process charts of semiconductor deviceswhich include bonding electrodes of the embodiments;

FIGS. 7A-7B are manufacturing process charts of semiconductor deviceswhich include bonding electrodes of the embodiments;

FIG. 8 is a cross-sectional figure which shows a schematic configurationof a modified example of semiconductor devices which include bondingelectrodes;

FIG. 9 is a figure which shows a configuration of a solid-state imagingapparatus; and

FIG. 10 is a figure which shows a configuration of an electronicapparatus.

DETAILED DESCRIPTION OF THE EMBODIMENT(S)

Hereinafter, preferred embodiments of the present disclosure will bedescribed in detail with reference to the appended drawings. Note that,in this specification and the appended drawings, structural elementsthat have substantially the same function and structure are denoted withthe same reference numerals, and repeated explanation of thesestructural elements is omitted.

Hereinafter, while example embodiments for implementing the presentdisclosure will be described, the present disclosure is not limited tothese examples.

Note that the description will be made in the following order.

1. Outline of a semiconductor device.

2. Embodiments of the semiconductor device

3. Method for manufacturing the semiconductor devices of the embodiments

4. Modified example of the semiconductor devices

5. Embodiments of an electronic apparatus

<1. Outline of a Semiconductor Device> [Configuration]

An outline of the configuration of bonding electrodes of a semiconductordevice will be described.

FIG. 1 shows a cross-sectional figure with the configuration of abonding section of a general semiconductor device of the related art.For this bonding section, there is a configuration of a plurality ofsemiconductor substrates, in which the wiring layers formed on each ofthe surfaces are opposite one another, and bonding electrodes formed onthe surfaces of the wiring layers are bonded to one other.

The bonding section shown in FIG. 1 denotes a state in which a firstbonding section 10 and a second bonding section 20 are bonded together.

The first bonding section 10 is formed on a semiconductor substrate,which is not shown in the figure. Also, the first bonding section 10includes a first interlayer insulating layer 11, and first bondingelectrodes 12. The first bonding electrodes 12 are formed within thefirst interlayer insulating layer 11, and the surface of the firstbonding electrodes 12 is exposed from the surface of the firstinterlayer insulating layer 11 on bonding surfaces. A barrier metalsurface 13, for preventing diffusion to the insulating layer of theelectrode material, is arranged on the surfaces in contact between thefirst bonding electrodes 12 and the first interlayer insulating layer11.

The second bonding section 20 is formed on a semiconductor substrate,which is not shown in the figure, different from that of the abovedescribed first bonding section 10. Also, the second bonding section 20includes a second interlayer insulating layer 21 and second bondingelectrodes 22. The second bonding electrodes 22 are formed within thesecond interlayer insulating layer 21, and the surface of the secondbonding electrodes 22 is exposed from the surface of the secondinterlayer insulating layer 21 on bonding surfaces. Further, a barriermetal surface 23, for preventing diffusion to the insulating layer ofthe electrode material, is arranged on the surfaces in contact betweenthe second interlayer insulating layer 21 and the second bondingelectrodes 22.

[Problem]

As described above, in a state where the surfaces on which the firstbonding electrodes 12 are formed and the surfaces on which the secondbonding electrodes 22 are formed oppose one another, the first bondingelectrodes 12 and the second bonding electrodes 22 are bonded to oneanother, and the first bonding section 10 and the second bonding section20 are laminated together. Here, the first bonding electrodes 12 and thesecond bonding electrodes 22 are bonded to one another in a deviatedstate where the bonding surfaces and the surfaces on which theelectrodes are formed do not completely match.

Further, the first bonding electrodes 12 and the second bondingelectrodes 22 are designed so that a difference in bonding areas is notgenerated, even in the case where the bonding position is deviated, byforming a large area on one of the electrodes so as to secure bondreliability.

Therefore, on the bonding surfaces there is a part where the bondingelectrodes come into contact, and there is a part where the bondingelectrodes and the interlayer insulating layer come into contact. Thatis, at the bonding surfaces of this semiconductor device, there is acontact section 14 where the first bonding electrodes 12 and the secondinterlayer insulating layer 21 come into contact. In addition, there isa contact section 24 where the second bonding electrodes 22 and thefirst interlayer insulating layer 11 come into contact.

At the contact sections 14 and 24, the bonding property is low sincedifferent materials are in contact with each other, such as the metalmaterial which constitutes the bonding electrodes and an inorganic oxideor the like which constitutes the interlayer insulating layers. Whensuch a bonding property is low, there are cases where a void (hole) willbe generated in the interface between the first bonding electrodes 12and the second interlayer insulating layer 21, and in the interfacebetween the second bonding electrodes 22 and the first interlayerinsulating layer 11. In this case, a problem may occur in the bondingproperty of the semiconductor device, such as deterioration of thebonding property.

Further, as shown in FIG. 2, there is a possibility that a leak path 15will form due to diffusion into the interlayer insulating layer of themetal, for example Cu, which constitutes the bonding electrodes. Thiscauses defects in the insulating property of the semiconductor deviceand problems in the barrier property.

In the bonding of the semiconductor substrates, if there is aconfiguration in which the bonding electrodes and the interlayerinsulating layer are not in contact with each other, by exactly matchingand bonding the bonding electrodes of the bonding interface, the abovedescribed problem will not not occur. However, it is difficult toeliminate the occurrence of a very slight deviation when bonding.Accordingly, it is difficult to improve the bonding property bypreventing a position deviation of bonding.

In addition, since the bonding areas of vertical bonding electrodes maynot be structurally identical, there will inevitably be a surface incontact between the bonding electrodes and the interlayer insulatinglayer.

Therefore, in semiconductor devices bonded by bonding electrodes, aconfiguration which prevents deterioration of the bonding property anddeterioration of the barrier property may be necessary, even in a statewhere position deviation has occurred.

<2. Embodiments of the Semiconductor Device> [Configuration of theSemiconductor Device]

Hereinafter, embodiments of the semiconductor device which includesbonding electrodes will be described.

FIG. 3 shows a schematic configuration of the semiconductor device whichincludes bonding electrodes of the embodiment of the present embodiment.FIG. 3 is a cross-sectional figure in the vicinity of a bonding sectionof the semiconductor device of the embodiment of the present embodiment.Note that in the above described semiconductor device 30 shown in FIG.3, a description of unnecessary wiring layers and the like will beomitted from the description of the present embodiment.

As shown in FIG. 3, the semiconductor device 30 includes an interlayerinsulating layer 32 formed on a semiconductor substrate 31, and bondingelectrodes 33 formed on the surface of this interlayer insulating layer32. In addition, a metal film 35 is included which covers the interlayerinsulating layer 32 and the surface of the bonding electrodes 33.

Various elements such as electronic circuits and wiring, which are notshown in the figure, are formed on the semiconductor substrate 31.

The layer formed on the outermost surface of the interlayer insulatinglayer 32 is composed, for example, from an oxide such as SiO, HfO, GeO,GaO or SiON, or from a nitride insulating layer and a metallic oxide.The other layers can use materials applied to an interlayer insulatinglayer of a semiconductor device which are well-known in the related art.The bonding electrodes 33 are formed from a material, for example Cu,applied to the electrodes of the semiconductor device which iswell-known in the related art.

A barrier surface layer 34 is formed from a material, for example Ta,Ti, Ru, TaN, TiN or the like, applied generally as a barrier metal layerin a semiconductor device.

The metal film 35 is formed by covering the entire surface of thesemiconductor device 30.

Further, it is possible for the metal film 35 to be bonded to thesemiconductor substrate by heat treatment, and a metal with a highconductivity can be used. In addition, the metal film 35 uses a metalwhich reacts with the interlayer insulating layer 32, in the parts incontact with the interlayer insulating layer 32, by heat treatment.Also, a metal is used in which a reaction product of the metal film 35becomes an insulator, which is generated by this reaction on the partsin contact with the interlayer insulating layer 32. For example, Ti, Taor the like are used as such a metal in the metal film 35.

Further, the metal film 35 is formed with a thickness at which all partsin contact with the interlayer insulating layer 32 become a reactionproduct due to the above described reaction. This is the thickness atwhich a conductive layer does not remain on the surface of the parts incontact with the interlayer insulating layer 32, after heat treatment.If a conductive layer remains on the surface, it will cause an increasein short circuits and leak currents between adjacent electrodes.Accordingly, while there is a difference due to the combination ofmaterials and the heat treatment condition, it is possible to have anentire reaction up to the surface by making the thickness of the metalfilm 35 equal to or less than 100 nm. Further, it is possible for theabove described characteristics to be favorably expressed by making thefilm thickness equal to or less than 20 nm.

Further, the metal film 35 is formed to a thickness at which thereaction product with the interlayer insulating layer 32 has asufficient barrier property, for example, a thickness equal to or morethan 5 molecular layers.

[Bonding of Semiconductor Devices]

Next, FIG. 4 shows a configuration in which two of the above describedsemiconductor devices 30 are laminated together. FIG. 4 showssemiconductor devices 30A and 30B, which have the same configuration.The semiconductor devices 30A and 30B are configured the same as theabove described semiconductor device 30 shown in FIG. 3, and are shownby attaching A and B to the respective reference numerals. Further,since each part of the semiconductor devices 30A and 30B has aconfiguration the same as the above described semiconductor device 30shown in FIG. 3, a description of them will be omitted.

Bonding between the semiconductor device 30A and the semiconductordevice 30B is performed on the surfaces where the bonding electrodes 33Aand 33B are formed, by metal films 35A and 35B arranged on the surfaceof the wiring forming side. The semiconductor substrates are laminatedtogether through the bonding electrodes 33A and 33B by this bonding.Further, the semiconductor device 30A and the semiconductor device 30Bare bonded in a state where the planar position between the bondingelectrode 33A and the bonding electrode 33B has been deviated.

The wiring forming surfaces of the semiconductor substrates 31A and 31Bare opposed to each other, and thereafter the above described bondingbetween the semiconductor device 30A and the semiconductor device 30Bcontacts both of them. Also, heat treatment is performed at a statewhere the metal film 35A and the metal film 35B are in contact with eachother, and the metal film 35A and the metal film 35B are bonded to oneanother. The semiconductor substrates 31A and 31B are laminated togetherby heating at the state where the metal films 35A and 35B are in contactwith each other.

Further, a reaction occurs in the parts where the metal films 35A and35B are in contact with the interlayer insulating layers 32A and 32B, bythe heat applied during bonding. When this reaction occurs, aninsulator, which is a reaction product between the metal film and theinterlayer insulating layer, is generated in the parts where the metalsfilms 35A and 35B are in contact with the interlayer insulating layers32A and 32B. Accordingly, the parts formed on the interlayer insulatinglayers 32A and 32B in the metal films 35A and 35B will form insulatingfilms 36A and 36B due to the reaction product.

Further, the metal films 35A and 35B formed on the bonding electrodes33A and 33B maintain the state of a formed film without change after theheat treatment.

For example, in the case where SiO₂ is used in the interlayer insulatinglayer 32A and Ti is used in the metal film 35A, a metallic oxide layer,which includes TiO₂ due to the above described reaction, will be formedon the interlayer insulating layer 32 as the insulating film 36A. TiO₂has a high barrier property or a high insulation property in order to beused as a general barrier metal.

Contact does not occur between the bonding electrodes 33A and 33B andthe interlayer insulating layers 32A and 32B, where the bonding propertyis low, due to the interlayer insulating layers 32A and 32B beingcovered by the insulating films 36A and 36B. Accordingly, a void is notgenerated in the bonding interface. Therefore, the reliability ofbonding the semiconductor devices is improved. In addition, diffusioninto the interlayer insulating layers 32A and 32B of the metal, forexample Cu, which constitutes the bonding electrodes 33A and 33B can beprevented. Accordingly, the formation of a leak path is controlled, andthe reliability of the semiconductor devices is improved.

Note that the metal films 35A and 35B may be bonded to both of thebonded semiconductor devices 30A and 30B, by using identical metalmaterials, or by using different materials such as Ti and Ta. Even inthe case of bonding by using different materials, it is possible to bondthe metals films 35A and 35B to each other, and when the metal film 35in contact with the interlayer insulating layer 32 becomes an insulatinglayer 36, the above described effect can be obtained.

<3. Method for Manufacturing the Semiconductor Devices>

Next, an example of a method for manufacturing the semiconductor deviceof the embodiments will be described. Note that the followingdescription of the manufacturing method will only show the manufacturingmethod in the vicinity of the bonding section of the above describedsemiconductor device 30 shown in FIG. 3, and a description of othermanufacturing methods for the configurations of the various elements,wiring or the like formed on the semiconductor substrate 31 will beomitted. A description of the fabrication methods for the semiconductorsubstrates, wiring layers, other various transistors and the variouselements will be omitted. These parts can be fabricated by well-knownmethods of the related art. Further, the same reference numerals areattached to configurations similar to those of the semiconductor devicesof the above described embodiments shown in FIGS. 3 and 4, and adetailed description of each of these configurations will be omitted.

First, as shown in FIG. 5A, an interlayer insulation layer 32 is formedon a semiconductor substrate 31, on which various elements are formed.The interlayer insulation layer 32 is formed by a plurality ofinterlayer insulating layers, wiring or the like. The figures are shownby omitting the stacking of the interlayer insulating layers, wiringlayers or the like.

Then, as shown in FIG. 5B, resist layers 41 are formed on the interlayerinsulation layer 32. The resist layers 41 are formed in a pattern whichopens positions for forming the bonding electrodes of the semiconductordevice.

As shown in FIG. 5C, the interlayer insulating layer 32 is etched to aprescribed depth, by a dry etching method which uses an etching deviceof a general magnetron system from above the resist layers 41, and opensections 42 are formed on the surface of the interlayer insulating layer32. After the etching process, an ashing process based on oxygen (O₂)plasma, for example, and a chemical process of an organic amine systemare applied as necessary, and the surface of the interlayer insulatinglayer 32 is washed.

Next, as shown in FIG. 6A, a barrier material layer 43 and an electrodematerial layer 44 are formed, so as to form barrier metal layers andbonding electrodes. The barrier material layer 43 is formed to 5-50 nmusing Ta, Ti, Ru, TaN or the like under an Ar/N₂ atmosphere, by an RFsputtering process. The electrode material layer 44 is formed with Cu orthe like on the barrier material layer 43, by using an electroplatingmethod or a sputtering method. The electrode material layer 44 is formedby embedding the formed open sections 42. Then, after the formation ofthe electrode material layer 44, heat treatment is performed forapproximately 1-60 minutes at 100° C. to 400° C., by using a hot plateor a sinter-annealing device.

Next, unnecessary parts are removed as a wiring pattern by aChemical-Mechanical Planarization (CMP) method, from among the depositedbarrier material layer 43 and the electrode material layer 44. By thisprocess, as shown in FIG. 6B, barrier metal layers 34 and bondingelectrodes 33 are formed.

Then, as shown in FIG. 6C, a metal film 35 is formed on the entiresurface by covering the surface of the bonding electrodes 33 and theinterlayer insulating layer 32. The metal film 35 forms a material, suchas Ti or Ta, to a thickness of 10-100 nm by using an ALD (Atomic LayerDeposition) method or a CVD (Chemical Vapor Deposition) method.

After the formation of the metal film 35, a flattening process isperformed on the surface by using a CMP method or the like as necessary.

According to the above described process, the semiconductor device 30can be formed.

Further, processes similar to the above described method in FIGS. 5A to6B are repeated, and a pair of semiconductor devices 30 are prepared.

Then, a Wet process which uses formic acid, for example, or a Dryprocess which uses plasma such as Ar, NH₃ or H₂, is applied to thebonding surfaces of the two semiconductor devices 30 formed by the abovedescribed method. An oxide film on the surface of the bonding electrodes33 is removed by this process, and a clean metal surface is exposed.

Then, as shown in FIG. 7A, the surfaces of the two semiconductor devicesare placed opposite one another. Then, both of the semiconductor devicesare brought into contact with one another. In such a state, both themetal films 35 do not change from the material at the time of filmformation, and the entire surface of both the semiconductor devices 30are covered.

At that time, heat treatment is performed for approximately 5 minutes to2 hours at 100° C. to 400° C., in an N₂ atmosphere at atmosphericpressure or within a vacuum, for example, by an annealing device such asa hot plate or an RTA.

By such a heat treatment, the metal film 35 of the parts in contact withthe interlayer insulating layer 32 reacts. In this way, an insulatingfilm 36, which includes a reaction product, is formed on the bondingsurfaces of both the semiconductor devices 30. In this way, at the sametime as the bonding of the semiconductor devices 30, the metal film 35and the interlayer insulating layer 32 reacts, and it is possible toform the insulating film 36.

According to the above described process, the semiconductor devices ofthe present embodiment shown in FIG. 7B can be manufactured.

Note that the formation of the insulating film 36 may be performed in aprocess different to that of the bonding of the semiconductor devices30. For example, after the metal film 35 has been formed in FIG. 6C,heat treatment may be performed on the semiconductor devices 30, and theinsulating film 36 may be formed.

<4. Modified Example of the Semiconductor Devices>

Next, a modified example of the semiconductor devices of the abovedescribed embodiments will be described.

FIG. 8 shows a configuration of the semiconductor devices of themodified example. The semiconductor devices shown in FIG. 8 have aconfiguration similar to the above described semiconductor devices shownin FIG. 4, except for the configuration of the metal films formed on thebonding surfaces. Accordingly, the same reference numerals are attachedto configurations similar to those of the semiconductor device shown inFIG. 4, and a description of them will be omitted.

For the semiconductor devices 50 shown in FIG. 8, one layer of the metalfilm 35 is formed on the bonding surfaces. In this way, thesemiconductor devices of the present embodiment may have a configurationwhere a metal film is formed only on the bonding surfaces of onesemiconductor device, and a metal film is not formed on the bondingsurfaces of the other semiconductor device. For example, thesemiconductor devices with the configuration shown in FIG. 8 have aconfiguration where a metal film 35A is formed on the bonding surfacesof the semiconductor device 30A, and a metal film is not formed on thebonding surfaces of the semiconductor device 30B.

Then, after the semiconductor device 30A and the semiconductor device30B have been laminated together, the metal film 35A of the parts incontact with the interlayer insulating layers 32A and 32B reacts due toperforming heat treatment, and becomes an insulating film 36A.

In the semiconductor devices 50 with the configuration shown in FIG. 8,while the metal film 35A of the parts in contact with the interlayerinsulating layers 32A and 32B becomes the insulating film 36A, the metalfilm 35A of the position placed between the bonding electrodes 33A andthe bonding electrodes 33B does not change into an insulating film.Accordingly, conduction between the bonding electrodes 33A and thebonding electrodes 33B can be secured by the metal film 35A.

Further, since the metal film 35A of the parts in contact with theinterlayer insulating layers 32A and 32B becomes the insulating film36A, the top of the interlayer insulating layers 32A and 32B are coveredby the insulating film 36A. As a result, contact does not occur betweenthe bonding electrodes 33A and 33B and the interlayer insulating layers32A and 32B, where the bonding property is low, and a reduction in thereliability of the bonding of the semiconductor devices, due to thegeneration of a void in the bonding interface, can be controlled.

In addition, diffusion into the interlayer insulating layers 32A and 32Bof the metal, for example Cu, which constitutes the bonding electrodes33A and 33B, can be prevented by the insulating film 36A covering thetop of the insulating layers 32A and 32B. Accordingly, the formation ofa leak pass is controlled, and the reliability of the semiconductordevices is improved.

<5. Embodiments of an Electronic Apparatus>

It is possible to apply the semiconductor devices of the above describedembodiments to an arbitrary electronic apparatus, for example, asolid-state imaging apparatus, a semiconductor memory, or asemiconductor logic device (such as an IC), which performs wire bondingby laminating two semiconductor members together.

[Solid-State Imaging Apparatus]

Hereinafter, an example of applying the configuration of electrodebonding in the above described embodiments to a solid-state imagingapparatus will be described.

FIG. 9 shows a schematic cross-sectional figure of the main sections ofa solid-state imaging apparatus according to the embodiment of thepresent embodiment. Note that in order to simplify the description inFIG. 9, the parts showing the barrier metal layer formed between theelectrode bonding sections, vias, and interlayer insulating layers willbe omitted.

The solid-state imaging apparatus 200 of the present embodiment includesa first semiconductor member 201 which has a photoelectric conversionsection 210, and a second semiconductor member 202 which has various MOS(Metal-Oxide-Semiconductor) transistors 220 constituting an operationcircuit. Further, the solid-state imaging apparatus 200 includes a colorfilter 203 and an on-chip micro lens 204.

In the solid-state imaging apparatus 200 of the present embodiment, thefirst semiconductor member 201 and the second semiconductor member 202are bonded together at a bonding interface. Further, in the presentembodiment, the color filter 203 and the on-chip micro lens 204 arestacked in this order on the top surface of the first semiconductormember 201 opposite to the side of the second semiconductor member 202(on a photoelectric conversion layer 211).

The first semiconductor member 201 includes a photoelectric conversionlayer 211 which has a photoelectric conversion section 210, and a firstmultilayer wiring section 212 arranged on the side of the photoelectricconversion layer 211 opposite the color filter 203.

The first multilayer wiring section 212 is configured by stacking aplurality of wiring layers 213. Each of the wiring layers 213 has aninterlayer insulating layer 214, first bonding sections 215 embeddedwithin the interlayer insulating layer 214, and vias 216 arranged forobtaining an electrical connection between layers (wiring layers 213 orthe photoelectric conversion layer 211) positioned from the layersthemselves to the color filter 203 side. Further, in the presentembodiment, an intermediate layer 217 is arranged between mutuallyadjoining wiring layers 213, and between the wiring layers 213 and thephotoelectric conversion layer 211.

On the other hand, the second semiconductor member 202 includes atransistor section 221 in which various MOS transistors 220 constitutingan operation circuit are formed, and a second multilayer wiring section222 arranged on the side of the transistor section 221 towards the firstsemiconductor member 201.

The second multilayer wiring section 222 is configured by stacking aplurality of wiring layers 223. Each of the wiring layers 223 has aninterlayer insulating layer 224, second bonding sections 225 embeddedwithin the interlayer insulating layer 224, and vias 226 arranged forobtaining an electrical connection between layers (wiring layers 223 orthe transistor section 221) positioned from the layers themselves to thetransistor section 221 side. Further, in the present embodiment, anintermediate layer 227 is arranged between mutually adjoining wiringlayers 223, and between the wiring layers 223 and the transistor section221.

In the solid-state imaging apparatus 200 with the above describedconfiguration, the configuration of the first bonding section and thesecond bonding section from any of the above described embodiments 1-3are respectively applied to the first bonding section 215 and the secondbonding section 225, which are bonded across a bonding surface. In thiscase, a solid-state imaging apparatus 200 can be obtained which has amore highly reliable bonding surface.

[Camera]

The above described solid-state imaging apparatus can be applied to anelectronic apparatus, such as a camera system of a digital camera, avideo camera or the like, a mobile phone which has an imaging function,or another apparatus which includes an imaging function. Hereinafter, acamera for example will be described as an example configuration of anelectronic apparatus.

FIG. 10 shows an example configuration of a video camera which canphotograph a still image or a moving image. A camera 300 of this exampleincludes a solid-state imaging apparatus 301, an optical system 302which guides incident light to a light receiving sensor section of thesolid-state imaging apparatus 301, a shutter device 303 arranged betweenthe solid-state imaging apparatus 301 and the optical system 302, and adriving circuit 304 which drives the solid-state imaging apparatus 301.In addition, the camera 300 includes a signal processing circuit 305which processes an output signal of the solid-state imaging apparatus301.

The solid-state imaging apparatus 301 is fabricated by using the bondingtechnique of metal electrodes from the embodiments and the modifiedexample according to the above described embodiment of the presentdisclosure. The configuration and function of each of the other sectionsare as follows.

The optical system (optical lens) 302 forms image light (incident light)from a photographic subject onto an imaging surface (not shown in thefigure) of the solid-state imaging apparatus 301. In this way, a signalcharge is stored, for a fixed period, in the solid-state imagingapparatus 301. Note that the optical system 302 may be configured by anoptical lens group which includes a plurality of optical lenses.Further, the shutter device 303 controls a light irradiation period anda light shielding period for the incident light of the solid-stateimaging apparatus 301.

The driving circuit 304 supplies a drive signal to the solid-stateimaging apparatus 301 and the shutter device 303. Also, the drivingcircuit 304 controls a signal output operation to the signal processingcircuit 305 of the solid-state imaging apparatus 301, and a shutteroperation of the shutter device 303, according to the supplied drivesignal. That is, in this example, a signal transfer operation isperformed from the solid-state imaging apparatus 301 to the signalprocessing circuit 305, according to the drive signal (timing signal)supplied from the driving circuit 304.

The signal processing circuit 305 applies various signal processes tothe signal transferred from the solid-state imaging apparatus 301. Also,the signal to which the various signal processes have been applied(video signal) is stored in a storage medium such as a memory (not shownin the figure), or is output to a monitor (not shown in the figure).

Additionally, the present technology may also be configured as below.

(1) A semiconductor device, including:

a semiconductor substrate;

an interlayer insulating layer formed on the semiconductor substrate;

a bonding electrode formed on a surface of the interlayer insulatinglayer; and

a metal film which covers an entire surface of a bonding surfaceincluding the interlayer insulating layer and the bonding electrode.

(2) The semiconductor device according to (1),

wherein the metal film includes a metal material which becomes aninsulator due to a reaction with the interlayer insulating layer.

(3) The semiconductor device according to (1) or (2),

wherein the metal film includes at least one type selected from Ta orTi.

(4) A semiconductor device including a first semiconductor substrate anda second semiconductor substrate which are formed by laminating surfacesof bonding electrodes through metal films, the semiconductor deviceincluding:

the first semiconductor substrate;

a first interlayer insulating layer formed on the first semiconductorsubstrate;

a first bonding electrode formed on a surface of the first interlayerinsulating layer;

the second semiconductor substrate bonded to the first semiconductorsubstrate;

a second interlayer insulating layer formed on the second semiconductorsubstrate;

a second bonding electrode formed on a surface of the second interlayerinsulating layer;

a metal film formed on a bonding surface between the first semiconductorsubstrate and the second semiconductor substrate, and between the firstbonding electrode and the second bonding electrode; and

an insulating film which is formed on the bonding surface between thefirst semiconductor substrate and the second semiconductor substrate,and on a part in contact with the first interlayer insulating layer orthe second interlayer insulating layer, and which includes a reactionproduct between the metal film and the first interlayer insulating layeror the second interlayer insulating layer.

(5) The semiconductor device according to (4), further including:

a first metal film formed on the first bonding electrode of the firstsemiconductor substrate;

a first insulating film which is formed on the first interlayerinsulating layer, and which includes a reaction product between thefirst metal film and the first interlayer insulating layer or the secondinterlayer insulating layer;

a second metal film formed on the second bonding electrode of the secondsemiconductor substrate; and

a second insulating film formed on the second interlayer insulatinglayer, and which includes a reaction product between the second metalfilm and the first interlayer insulating layer or the second interlayerinsulating layer.

(6) A method for manufacturing a semiconductor device, comprising:

forming an interlayer insulating layer on a semiconductor substrate;

forming a bonding electrode on a surface of the interlayer insulatinglayer; and

forming a metal film on an entire surface of the interlayer insulatinglayer and the bonding electrode.

(7) An electronic apparatus, including:

the semiconductor device according to any one of (1) to (5); and

a signal processing circuit which processes an output signal of thesemiconductor device.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

The present disclosure contains subject matter related to that disclosedin Japanese Priority Patent Application JP 2012-029429 filed in theJapan Patent Office on Feb. 14, 2012, the entire content of which ishereby incorporated by reference.

1. A semiconductor device, comprising: a semiconductor substrate; aninterlayer insulating layer formed on the semiconductor substrate; abonding electrode formed in the interlayer insulating layer such thatthe bonding electrode and the interlayer insulating layer form a planarsurface including a first region corresponding to the bonding electrodeand a second region corresponding to the interlayer insulating layer;and a metal film layer which covers the planar surface, wherein themetal film layer includes a material that reacts with the interlayerinsulating layer in a case where the material contacts the interlayerinsulating layer and is exposed to a heat treatment.
 2. Thesemiconductor device according to claim 1, wherein the material is ametal which becomes an insulator due to a reaction with the interlayerinsulating layer.
 3. The semiconductor device according to claim 1,wherein the material includes at least one type selected from Ta or Ti.4. A semiconductor device including a first semiconductor substrate anda second semiconductor substrate which are formed by laminating surfacesof bonding electrodes through metal films, the semiconductor devicecomprising: the first semiconductor substrate; a first interlayerinsulating layer formed on the first semiconductor substrate; a firstbonding electrode formed in the first interlayer insulating layer suchthat the first bonding electrode and the first interlayer insulatinglayer form a first planar surface including a first region correspondingto the first bonding electrode and a second region corresponding to thefirst interlayer insulating layer; the second semiconductor substratebonded to the first semiconductor substrate; a second interlayerinsulating layer formed on the second semiconductor substrate; a secondbonding electrode formed in the second interlayer insulating layer suchthat the second bonding electrode and the second interlayer insulatinglayer form a second planar surface including a third regioncorresponding to the second bonding electrode and a fourth regioncorresponding to the second interlayer insulating layer; a first metalfilm layer formed between the first planar surface and the second planarsurface, wherein the first metal film layer includes a first materialthat reacts with the first interlayer insulating layer in a case wherethe first material contacts the first interlayer insulating layer and isexposed to a heat treatment. 5-6. (canceled)
 7. An electronic apparatus,comprising: a semiconductor device which includes a semiconductorsubstrate, an interlayer insulating layer formed on the semiconductorsubstrate, a bonding electrode formed in the interlayer insulating layersuch that the bonding electrode and the interlayer insulating layer forma planar surface including a first region corresponding to the bondingelectrode and a second region corresponding to the interlayer insulatinglayer, and a metal film layer which covers the planar surface; and asignal processing circuit configured to process an output signal of thesemiconductor device, wherein the metal film layer includes a materialthat reacts with the interlayer insulating layer in a case where thematerial contacts the interlayer insulating layer and is exposed to aheat treatment.
 8. The semiconductor device according to claim 1,further comprising a barrier surface layer between the interlayerinsulating layer and the bonding electrode.
 9. The semiconductor deviceaccording to claim 1, wherein the barrier surface layer includes amaterial selected from the group consisting of Ta, Ti, Ru, TaN, and TiN.10. The semiconductor device according to claim 1, wherein theinterlayer insulating layer includes an oxide, or a nitride layer and ametallic oxide.
 11. The semiconductor device according to claim 1,wherein the bonding electrode includes Cu.
 12. The semiconductor deviceaccording to claim 1, wherein a thickness of the metal film layer isequal to or less than 100 nm.
 13. The semiconductor device according toclaim 9, wherein a thickness of the metal film layer is equal to or lessthan 20 nm.
 14. The semiconductor device according to claim 4, furthercomprising a barrier surface layer between the first interlayerinsulating layer and the first bonding electrode.
 15. The semiconductordevice according to claim 4, further comprising: a second metal filmlayer formed between the first planar surface and the second planarsurface, wherein the second metal film layer includes a second materialthat reacts with the second interlayer insulating layer in a case wherethe second material contacts the second interlayer insulating layer andis exposed to the heat treatment.
 16. The semiconductor device accordingto claim 15, further comprising: a first barrier surface layer betweenthe first interlayer insulating layer and the first bonding electrode;and a second barrier surface layer between the second interlayerinsulating layer and the second bonding electrode.
 17. The semiconductordevice according to claim 4, wherein the first interlayer insulatinglayer and/or the second interlayer insulating layer includes an oxide,or a nitride layer and a metallic oxide.
 18. The semiconductor deviceaccording to claim 4, wherein the first bonding electrode and/or thesecond bonding electrode includes Cu.
 19. The semiconductor deviceaccording to claim 4, wherein a thickness of the first metal film layeris equal to or less than 100 nm.
 20. The semiconductor device accordingto claim 19, wherein a thickness of the first metal film layer is equalto or less than 20 nm.
 21. The semiconductor device according to claim4, wherein a thickness of a reaction product of the first metal filmlayer and the first interlayer insulating layer is equal to or more than5 molecular layers.
 22. An electronic apparatus comprising: thesemiconductor device according to claim 4; and a signal processingcircuit configured to process an output signal of the semiconductordevice.